Progressive multifocal rigid gas permeable contact lens

ABSTRACT

A contact lens is provided. It is a rigid gas permeable, corneal-scleral progressive, multifocal, vision lens that covers the cornea and a portion of the sclera of an eye. It is particularly beneficial for use on patients who have undergone refractive surgery and/or on patients experiencing presbyopia. The lens is designed to have dual touch contact with an eye. One contact point is the central portion of the cornea and the other contact point is a portion of the sclera.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. patent application Ser. No.12/762,347, titled “Progressive Multifocal Rigid Gas Permeable ContactLens,” filed on Apr. 18, 2010, and to provisional Application61/172,994, filed Apr. 27, 2009 and also to provisional Application61/173,579, filed Apr. 28, 2009. All three of these applications arehereby incorporated by reference in their entireties.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention is related to contact lenses and rigid gas permeable(“RGP”) corneal-scleral contact lenses in particular. The lens set forthherein is a progressive vision lens designed to cover the cornea and asmall portion of the sclera of the eye.

More particularly, the lens presented here allows for a near centeraspheric addition to create a true progressive rigid gas permeablecontact lens. The lens will correct for the lack of accommodation“presbyopia” in all eyes that are normal or unaltered and in eyes thathave been altered by refractive surgery or any surgical procedure thatmodifies or changes the shape of the cornea such as transplants.

2. Description of the Art

The art in the contact lens field is replete with innovations in contactlens designs for both post refractive, bifocal and multifocal lenses.However, the application of a progressive multifocal corneal sclera lensthat also allows a post refractive lens with the addition of aprogressive multifocal in a corneal-scleral lens is unique. The agingpopulation is growing worldwide. Today's refractive surgery patients inmost cases had the procedure done to rid them of the need to wearspectacle lenses but as they age they develop presbyopia. This conditionrenders the eye with a decreasing amount of accommodation or the abilityto transition from near to distance vision. The aging population isremaining active longer and requires a lens with continuous vision thatcan match their active lifestyle. The invention has been successfullyused to provide corrections of a surgically altered cornea for myopia,hyperopia, and presbyopia. The lens, by its design, providing aprogressive near center aspheric near addition with a diameter thatcovers both the cornea and a portion of the sclera, allows for a fitthat corrects presbyopia in both normal and surgically altered corneas.

The lenses presented here work well in treating patients with visualdeficiencies resulting from post refractive surgery errors and agerelated presbyopia in both normal and surgically altered eyes.

Furthermore, this invention relates to methods of the design andapplication of lenses and the means to obtain measurements from the eyeby the use of pre-op and post-op keratometry readings, diagnosticlenses, topography readings and/or a combination of these.

Corneal contact lenses that are supported entirely on the cornea haveproblems that are solved through the use of a corneal-scleral lens aspresented here. In a corneal lens all the functions of the lens takeplace on the cornea. This includes both near and distance vision, tearexchange curves for comfort, curves to center the lens and curves foredge contour. Each part of a corneal lens has a fitting duty and in somecases such as a translating or bifocal or multifocal. This presents adistinct problem such as vision and acuity loss during the transitionalmovement of the lens from the near and distance optical component of thelens. This results in a compromise to continuous vision correction. Byplacing a progressive multifocal segment in the center of the anteriorsurface of the lens the result is continuous vision throughout thetransition from near to distance vision in a controlled rate. The largerdiameter of the corneal-scleral lens, usually between 12.5 and 17.0 mmgives the lens its reliable centering. The larger diameter of the lensis also responsible for its high degree of comfort. This is possible asthe edges of the lens are always under both the upper and lower eyelidminimizing the foreign body sensation as the eyelid performs itsblinking function. It also increases comfort by distributing the weightand pressure of the lens over the cornea and a small portion of thesclera.

This application is related to rigid gas permeable contact lenses of thetype set forth in U.S. Pat. No. 5,929,968 to Cotie and Hirshberg titledScleral-Corneal Contact Lens which is incorporated by reference in itsentirety herein. The lens set forth in U.S. Pat. No. 5,929,968 is asingle vision lens for orthokeratology applications and is not aprogressive multifocal rigid gas permeable lens.

In contact lenses there are designs to provide for bifocal vision. Thesedesigns include the most common type of bifocal contact, the translatingbifocal. In this system eyelid contact with the lens will facilitatemovement of the lens from a near object focus position to a distancepower portion of the lens. In this example the near power is on thebottom of the lens. A system is used to keep the lens from rotating onthe eye. When the patient looks downward to focus on a near object thelens translates up so the eye is looking through the near or add powerat the bottom of the lens. When the person looks up and blinks the uppereyelid “catches” on the top portion of the lens forcing it downwardallowing the patient to use the distance power portion of the lens.Because of the contact of the upper lid with the edge of the lens acomfort issue most often referred to as a foreign body sensation iscaused. The use of the translating method also gives the unwanted lostof vision as the lens moves from distance to near during the blinkingprocess.

In other methods of providing bifocal vision a mono vision situation isused to accomplish bifocal vision. This type of vision correction forpresbyopes uses two single vision contact lenses one having theprescriptive power of the distance prescription in one eye and the otherhaving the prescription for the near power in the other eye. The problemwith this method is “simultaneous vision.” This is were the eyes seesboth near and distance at the same time. This method requires thepatient to have an adaptation period were the brain is trained to seeonly the image that it requires and to ignore the other. This can insome patient cause a loss of depth perception. Some patients never fullyadjust to this type of vision and the time of adaptation for those whocan, varies from a short period of several days to a period of manydays. Many patients simply discontinue the use of such contacts.

In this technique two single vision lens are used, one in each eye. Onelens will have a prescriptive power of the distance prescription in oneeye and the prescriptive power for the near power in the lens for theother eye. A refinement of this lens is to have one of the lenses beinga bifocal lens however this has not proven to be a well acceptedsolution to the need for a bifocal contact lens.

Another method of vision correction in contact lens is the concentricbifocal that uses a system of corrective rings that alternate betweennear and far vision.

This method is also of the “simultaneous vision” mode where the brain is“seeing” both near and distance and the same time. This causes thepatient to undergo the same type of adaptation problems as withmonovision lens sets. The number of rings that are available to the eyeis dependant upon pupil size, which will vary due to ambient lightingconditions. In most cases at least two rings are available.

With current small diameter rigid gas permeable lenses that float on theeye there is not enough stability for acceptable vision.

Each of these methods of providing bifocal vision have not beensuccessfully and widely adopted as there are fit and comfort issues witheach of these lens types. Only very motivated patients have beensuccessful in continuing to wear theses types of lenses.

BRIEF SUMMARY OF THE INVENTION

The present invention provides, among other things, a rigid gaspermeable lens that covers the cornea and a portion of the sclera of aneye. The lens is formed with a progressive vision prescription. Thislens has a radial outer portion that generally conforms to the shape ofthe ocular surface in the scleral region. The posterior surface of thelens covering the corneal region of the eye is selectively spaced from,aligned with or in eyelid bearing pressure contact with the cornealregion of the eye.

The effect of the stability of a lens using a larger diameter contactlocation is well known. The lens disclosed here uses the added stabilityinducing design of dual touch or dual contact. The inventors' lens hasphysical touch or contact on both the central portion of the cornea anda portion of the sclera. By affecting a touch pattern that comes incontact with two portions of the eye the lens of this design spreads theweight of the lens and the downward force of the eye lid onto twoseparate areas of the eye. This leads to a lens having increased comfortrelative to other lenses on the market. Not only is comfort increasedbut this lens design also adds greatly to the stability of the lensafforded by this design. Because of the high Dk (oxygen transmitting orpermeability) materials used in the production of the lens disclosedherein movement can be restricted and still maintain healthy corneas.This allows the vision correcting and fitting curves to maintain thepositions that they were designed to be in. This increases visualacuity, and the total eye health as it pertains to the wearing ofcontact lenses.

The invention is directed to solving the problems of both the personthat has had refractive surgery or non-altered corneas and those thatare now experiencing the effects of presbyopia. Either problem can beaddressed by the use of the lenses disclosed herein. Presbyopic eyesneed more oxygen, have less corneal sensitivity, increased positivespherical aberrations and may see poorly in low light. A presbyopic eyealso experiences increased light scatter resulting in glare, and mayhave a smaller pupil size. Also the post refractive surgery eye willgenerally have a flatter optical zone with more normal peripheral areaand can experience increased glare especially at night. Another problempost refractive surgery is the possibility of developing a conditionknown as ectasia. The lenses provided by this invention recognize thesepost refractive surgery possibilities and provide a cornea-scleral lensthat improves the vision of the person with some of these maladies. Allof the above conditions respond favorably to the use of acorneal-scleral progressive multifocal lens including but not limited topatients with post refractive surgical problems.

The lenses of this invention can be manufactured from a variety ofmaterials including soft and GP and PMMA materials. GP materials of highDK values are the preferred medium because of the better visual acuitythat is obtained by using a material that is more stable and has littleto no flexure and because of its high oxygen transmission that providesexcellent eye health.

This type of contact lens have not been doable until now because of thelack of a large diameter lens that provided a solid workable platform toplace the aspheric add zone on the convex side of the lens. With ascleral corneal lens the lens is well stabilized on the eye allowing fora true progressive multi-focal RGP contact lens.

One object of the lens is to provide a progressive multifocal lens thatcan be worn by patients with emerging presbyopia and patients with moreadvanced presbyopia with or without surgical alteration to the cornea.

One object of the invention is to provide a post refractive lens withthe addition of a progressive multifocal in a cornea-scleral lens.

Another object of the invention is to provide a lens that providescorrections of a surgically altered cornea for myopia, hyperopia, andpresbyopia.

Also an advantage of the lens presented here is the feature of the lenslimiting, because of its larger diameter of the lens, the exposure ofthe wearer's eye to the harmful effects of ultraviolet radiation on alarger portion on the eye and it structures.

Another advantage is that true progressive multi-focal prescriptions arecan be translated into soft lenses.

Another advantage of this lens is that there is near “instant vision”when changing focus from a near object to an intermediate or far object,and vice-versa.

Another advantage of the invention is that it allows for a near asphericcenter addition in an RGP corneal-scleral contact lens.

A further advantage of the lens presented here is that the lens helps toprotect the sensitive T cell regeneration area of the eye by aligningwith or vaulting the limbus.

Another advantage of this lens is that it is comfortable to wear sincethe lens fits under both the upper and lower eye lid eliminating theforeign body sensation during the blinking process.

Also an advantage to this lens is that it is not prone to unintendeddislodgement during periods of physical activity making it useful forpatients involved in sports.

Another advantage over soft lenses is the loss of visual acuity duringthe blinking process with can cause a soft lens to “fold” or distortcausing a loss of clear vision during periods of physical activity. Thismaking it desirable for many sports activitities that can be enhanced byvision that is not compromised by loss of continues vision.

Another advantage of the lens is that it offers a unique combination ofvisual and comfort benefits not available in contact lenses to date.

One object of the invention is to provide a lens that can be worn aftersurgical treatment of the cornea such as post refractive surgery orcorneal transplants surgery.

Another object of the invention is to provide a lens with progressivemulti-focal capability to address presbyopia.

Both of the above objects can be used separately or combined together.

Another object of the invention is to provide a lens with progressivemulti-focal capability to address the effects of presbyopia that may setin after refractive surgery.

Another object of the invention is to provide a lens giving a wearercontinuous vision that can match the active lifestyle of aging wearers.

Another object is to provide a contact lens that is comfortable to wearand easy to insert and remove.

A further advantage of this lens is that it is thinner and much smallerthan previous scleral contact lenses. This lens conforms to the corneaand a small portion of the sclera to provide a distributed bearing areafor the lens.

It is an object of the invention to provide a lens that is not easilydislodged.

Also an advantage is that visual performance is consistent with rigiddesigns.

Aspects and applications of the invention presented here are describedbelow in the drawings and detailed description of the invention. Unlessspecifically noted, it is intended that the words and phrases in thespecification and the claims be given their plain, ordinary, andaccustomed meaning to those of ordinary skill in the applicable arts.The inventors are fully aware that they can be their own lexicographersif desired. The inventors expressly elect, as their own lexicographers,to use only the plain and ordinary meaning of terms in the specificationand claims unless they clearly state otherwise and then further,expressly set forth the “special” definition of that term and explainhow it differs from the plain and ordinary meaning Absent such clearstatements of intent to apply a “special” definition, it is theinventors' intent and desire that the simple, plain and ordinary meaningto the terms be applied to the interpretation of the specification andclaims.

The inventors are also aware of the normal precepts of English grammar.Thus, if a noun, term, or phrase is intended to be furthercharacterized, specified, or narrowed in some way, then such noun, term,or phrase will expressly include additional adjectives, descriptiveterms, or other modifiers in accordance with the normal precepts ofEnglish grammar. Absent the use of such adjectives, descriptive terms,or modifiers, it is the intent that such nouns, terms, or phrases begiven their plain, and ordinary English meaning to those skilled in theapplicable arts as set forth above.

Further, the inventors are fully informed of the standards andapplication of the special provisions of 35 U.S.C. §112, ¶6. Thus, theuse of the words “function,” “means” or “step” in the DetailedDescription or Description of the Drawings or claims is not intended tosomehow indicate a desire to invoke the special provisions of 35 U.S.C.§112, ¶6, to define the invention. To the contrary, if the provisions of35 U.S.C. §112, ¶6 are sought to be invoked to define the inventions,the claims will specifically and expressly state the exact phrases“means for” or “step for, and will also recite the word “function”(i.e., will state “means for performing the function of [insertfunction]”), without also reciting in such phrases any structure,material or act in support of the function. Thus, even when the claimsrecite a “means for performing the function of . . . ” or “step forperforming the function of . . . ,” if the claims also recite anystructure, material or acts in support of that means or step, or thatperform the recited function, then it is the clear intention of theinventors not to invoke the provisions of 35 U.S.C. §112, ¶6. Moreover,even if the provisions of 35 U.S.C. §112, ¶6 are invoked to define theclaimed inventions, it is intended that the inventions not be limitedonly to the specific structure, material or acts that are described inthe preferred embodiments, but in addition, include any and allstructures, materials or acts that perform the claimed function asdescribed in alternative embodiments or forms of the invention, or thatare well known present or later-developed, equivalent structures,material or acts for performing the claimed function.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring to the detailed description when considered in connection withthe following illustrative figures may derive a more completeunderstanding of the present invention. In the figures, like referencenumbers refer to like elements or acts throughout the figures.

FIG. 1 is a lens showing the sections of the lens directed to near,intermediate and distance prescription corrections.

FIG. 2 is a presentation of a known style of translating lens.

FIG. 3 is a presentation of a known style of concentric lens.

FIG. 4 is an illustration of an aspheric lens.

FIG. 5 is a process flow chart showing the normal fitting andmanufacturing of the lens of the invention.

Elements and acts depicted in the figures are illustrated forsimplicity. They are presented to illustrate the invention to assist inan understanding thereof. The figures have not necessarily been renderedaccording to any particular sequence, size, scale or embodiment.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, and for the purposes of explanation,specific details are set forth in order to provide an understanding ofthe various aspects of the invention. It will be understood, however, bythose skilled in the relevant arts, that the present invention may bepracticed without these specific details. In other instances, knownstructures and devices are shown or discussed more generally in order toavoid obscuring the invention. In many cases, a description of theoperation is sufficient to enable one to implement the various forms ofthe invention, particularly when the operation is to be implemented insoftware. It should be noted that there are many different andalternative configurations, devices and technologies to which thedisclosed inventions may be applied. The full scope of the invention isnot limited to the examples that are described below.

This invention incorporates a design that will provide opticalcorrection for an eye that has developed presbyopia and also for an eyesubsequent to surgical treatment of a defined portion of the cornea andthe onset of presbyopia. The contact lens presented here has a centralarea that is adapted to be optically aligned with the lens of the eyeand provides optical correction to light passing through the eye lens.The lens has a posterior surface in substantial abutment with acorresponding predefined surface of the cornea. In the post refractivesurgical design the lens has an intermediate portion surrounding thecentral portion that has a posterior surface that is spaced from thesurface of the surgically treated portion of the cornea, and aperipheral portion that has a posterior surface in substantial abutmentwith a predetermined surface area of the sclera of the eye. The centraland peripheral portions of the posterior surface of the lens cooperateto control and distribute the bearing pressure imposed on the lens by aneyelid when the eyelid is moved over the anterior surface of the lens.

In the design to fit non-surgically altered corneas the above design isthe same only it is fit over the center of a non-altered cornea. Thisdesign is for normal eyes that have an un-altered cornea.

The anterior surface of the lens is fitted with an aspherically designedsegment centrally located at a pre-defined diameter that providescorrection for an eye that is experiencing presbyopia. This asphericallydesigned segment is located in a predefined central area that is adaptedto be optically aligned with the lens of the eye and provide opticalcorrection to light passing through the eye lens for near visioncorrection.

In the design of this lens there is a range of parameters that are usedin the final embodiment of the lens. It has been found that a standardcurve ranges of the fitting set can range from 7.34 mm to 8.33 mm forthe progressive multifocal set.

It is also known by the inventors that the range of the lenses that canbe produced is limited only by the combination of the prescriptivepower, diameter, and lathe or other processing equipment range.Extremely flat and high curves are possible because of the fittingdiameters that place the lens touch on both the cornea and the sclera.

Sagittal depth for this lens is dependent upon the peripheral curve thatis chosen during the lens fitting of a particular patient. This isimportant because after fitting the peripheral curve/sclera portion ofthe lens a base curve is chosen that will fit the central portion of thecornea without altering the sagittal height of the lens. This allows thepractitioner to know how the lens will ultimately fit when both theperipheral curve portion and the base curve portion are married togetherto form the final lens.

Zone sizes for each lens is dependent upon the prescription and theperipheral and base curves that will be married together. The adjustmentof each curve places the correct curve in the correct areas of thecornea and sclera so to best fit these areas and allow the lens tocontour to the total geometry of the eye and achieve high stability. Thezone sizes in the optical center are dependent upon the choice of thefitting set lens that was chosen for the peripheral curve. Adjustment ofthe curve zone size allows the lens to maintain the same sagittal heightwhen adding steeper or flatter base curves.

In this lens development add zones and powers are determined by theprescription that was produced by the practitioner during the refractionprocess of the eye exam. A determination is made as to which eye is thedominant eye. Next a determination of the initial add zone size, byusing the diameter of the pupil of the eye in normal room illumination,will be made. This dilating of the pupil is the process that allows theeye to transition from near to distance vision. The non-dominant eyewill have a larger initial add zone size by 0.50 mm.

The add power is determined by the spectacle add power determined duringthe eye exam. In the dominant eye we will use an add power that is 0.50D less than the spectacle add. In the non-dominant eye we will use thefull spectacle add power.

The lens of this invention can be made in the diameter range of fromabout 13.0 mm to about 16.0 mm. This range will cover the range from amicro cornea to an extra large cornea. This gives the lens an optimalrange that will allow the prescriptive and landing curves to be placedin the area that will provide the best vision, eye health, and comfort.

Because of the aspheric design of the center addition power thedisclosed lens provides the patient continuous vision from distance tonear. Such continuous vision cannot be accomplished with other types ofmultifocal contact lenses, such as, but not limited to, the translatinglens in which the lens must move from its distance component to the nearvision component causing the loss of clear vision during the translationfrom distant to near vision. The design of the aspheric center additiongives the patient clear, accurate vision throughout the range from nearto distance when fit correctly.

The lens of this invention also allows a patient that has had refractivesurgery for health or cosmetic reason to continue to wear contactlenses. This has the potential to include a large portion of thepopulation that has had refractive surgery the opportunity to remain incontact lenses for both health and cosmetic reasons. The geometry of theeye after surgery has been altered in a treatment zone in the center ofthe cornea. Because this lens is a larger diameter it provides greatfitting flexibility for patients with surgically altered eyes. Thestandard smaller corneal lenses that sets only on the cornea has a muchharder time adapting to the large changes in geometry between thetreatment area and the non surgically altered portion of the eye.

The corneal-scleral progressive multifocal post refractive surgical lensis formed from a high Dk rigid gas permeable material and has a flatcentral posterior surface (base curve). This flat area, also known as areverse curve, is flatter than the remaining three curves, namely thesecondary curve, the intermediate curve, and the peripheral curve. Theselast three curves are steeper than the base curve. This design allowsthe fitting of the portion, the treatment area, of the cornea that hasbeen ablated during refractive surgery.

This lens has been found to be more comfortable to wear than aconventional contact lens for both patients with normal refractiveerrors and those who have had refractive surgeries. The lens presentedhere is designed to rest on the eye under both the upper and lowereyelid. Because the lens is already under both lids the feeling of aforeign body being in the eye is greatly reduced. This causes the lensto be extremely comfortable. In older designs that were smaller andrested entirely on the cornea, the upper and lower eyelids made contactor bumped into the edge of the lens each time the eye blinked. Thisblink contact with the edge of a lens causes an uncomfortable sensationthat led many patients to discontinue use of conventional contactlenses.

Three methods of fitting the posterior surface of the lens to the eyeare available.

A first fitting procedure when fitting the post refractive designinvolves using the pre-surgical keratometer reading of the eye beforethe surgical procedure was preformed for the secondary, intermediate,and peripheral curves. Then assessing the keratometer readings of thetreatment zone of the post surgical cornea to be used for the basecurve.

The second method which is the preferred method for both standard andpost refractive corneas is to use a fitting set or a set of diagnosticlenses to determine the best fit of the secondary, intermediate, andperipheral curves. For the standard refractive error cornea fitting thecentral cornea or base curve with another or the same lens from thefitting set to yield a correct fit. For the post refractive surgerypatient the practitioner will then use the keratometer readings of thepost surgically altered treatment area to adapt the base curve to fit.

The third method is to use a specifically designed diagnostic lens setto fit both the surgically altered treatment area and the secondary,intermediate, and peripheral curves.

The anterior surface of the lens contains the addition or segment thatprovides for the correction for the near and intermediate readingdistances. This is fit by determining the base refraction for distancevision and addition power for the anterior aspheric segment for nearvision. Then measuring the pupils of both eyes in normal roomillumination to determine the size of the add zone. The dominant eyemust also be ascertained. Using the above information the bifocal canthen be determined.

When an object is held at a distance the pupil dilates to a largerdiameter effectively utilizing the distance portion of the lens. Anobject held closer to the eye will dilate the pupil to a smallerdiameter effectively utilizing the near portion of the lens.

The post refractive design of this invention will provide optical orvisual correction for the lens of the eye after surgical treatment, suchas a radial keratotomy, Lasik (laser in situ keratomileusis), or anyother surgical treatment of the eye that changes the shape of thecornea. For example, when used after failed corneal surgery, or as anadjunct to partially successful surgery, the intermediate portion of thelens is desirably spaced from the surgically treated corneal surface.The eyelid bearing pressure is controllably distributed over the scleraland central corneal surfaces. If it is desired to flatten the centralcorneal region, the corresponding area of the posterior surface of thelens is desirably flattened, that is has a larger radius or curvaturethan the ocular surface of the central cornea.

For those eyes that have been modified by surgical treatment to thecornea to correct vision and are now suffering from presbyopia, theaddition of an aspherical surface of predetermined diameter andcurvature is added to the anterior surface of the lens to correct fordeficiencies' in near vision.

Turning to FIG. 1. This is the lens of the invention shown generally as10. FIGS. 2-4 are lenses known in the art and are discussed below.

The lens of this invention is a rigid gas permeable lens (“RGP” lens).FIG. 1 is a representation of an aspheric multifocal contact lens whereboth distance and near prescriptions are placed in the central visualarea, on or close to the pupil. The lens 10 will cover the cornea and aportion of the sclera while bridging the limbus. This lens is designedto vault or align with the limbus. The design helps to protect thesensitive T cell regeneration area of the eye. By aligning with orvaulting the limbus pressure on this area is eliminated. Having theperiphery of this lens touch the sclera of the wearer's eye makes thislens different from the lenses currently being made. None of the lensesknown to the inventors are aspheric multifocal lenses that cover thecornea and at least a portion of the sclera. The front surface, by theaddition of a multifocal structure, is designed to provide continuousvision, that is, constant progressive vision, in the near, intermediate,generally 14, and distance, generally 16 fields of view. The frontsurface of the lens has an adjustable aspherical central zone that iscalculated by measuring the wearer's pupil diameter in normal roomillumination, which is than designed to provide near vision, generally12. The front surface also incorporates an adjacent adjustable sphericalportion that is designed to provide distance vision, generally 16.Because of the unique nature of the concave side of the lens and largediameter (13.3 mm to 16.0 mm) which by design minimizes movement hasallowed the use of the near center add to be very effective. Themovement of the patient's gaze is the control mechanism in moving fromdistance to near vision. When the wearer views and object at a closedistance the pupil dilates down to a small aperture allowing the wearerto see through the central portion 12 of the lens which is the addition(“add”) area used for reading or close work. When the wearer views anobject in the distance the pupil dilates to include the distance portionof the lens 16 and give excellent distance vision. As the wearer's gazemoves through the intermediate distance range the aspheric portion ofthe lens, generally 14, also provides vision in the zones that wouldinclude tasks, such as, for example, but not limited to, computer use.Other attempts using a near center add have not been successful becauseof movement of the lens in general and folding of the lens (in the caseof soft contact lenses). This misalignment has limited the wearer'sability to use the near and distance zones effectively causing blurredvision. The aspherical near and the spherical distance portions on theconvex surface of the lens merge in a progressive design to avoid astark juncture and provide continuous vision between distanceintermediate and near objects.

This lens design allows diopter additions on the front surface of thelens.

This rigid gas permeable multifocal design is placed on the convexportion of the lens and is designed to work more like a progressiveeyeglass lens where the different prescriptive powers are lathed in anaspherical and spherical design to provide continuous vision throughoutthe movement of the wearer's gaze from distance to near vision. Thistechnique more closely emulates the eye before the onset of presbyopia.

Spherical center add uses a method in which a near power of varying sizeis lathed in the center of the contact lens. The rest of the opticalportion of the lens in lathed to provide distance vision. This designworks better than the others detailed below in the discussion of FIGS.2-4 but because of the spherical nature of the lens it can only providedistance and near vision. The distance and near only design leaves outthe important intermediate vision area that persons having presbyopiarequire in order to allowing them the use computers and other devicesthat require intermediate vision.

FIG. 2 is a depiction of a known translating lens, generally 30. In thislens the near 32, and far 34, prescription zones are distinct. Thewearer's pupil moves from one zone to another depending on the wearer'svisual need at the moment. In this translating lens the nearprescription 32 is usually placed at the bottom of the lens. Thedistance prescription 34 is placed at the top of the lens. This issimilar to bifocal eyeglasses. In some situations this is reversed andthe near prescription is place at the top. This may be beneficialdepending on the needs of a wearer's work or hobby.

Translating lenses, such as shown in FIG. 2, may rotate when the wearerblinks. Thus some translating lenses are weighted or ballasted, at thebottom to keep the lens properly positioned on the wearer's eye. Anotherway of controlling a translating lens is to have it flattened ortruncated at the bottom. In this embodiment the lower eyelid willsupport and shift the lens upward when the wearer needs access to thenear vision zone.

Translating lenses are more adaptable to small pupils although they canaccommodate large pupils, but not as effectively. Translating lensesalso have other problems not inherent in the instant invention. Theseinclude the need for a translating lens to move freely on the eye inorder to re-center. Wearers with habitual dry eyes are not goodcandidates for translating lenses. Another problem with translatinglenses is that weakened muscle capability in upper eyelids may allow theeyelid to interact with the lens too much. This may be problematic inolder wearers.

FIG. 3 is a representation of a concentric or annular lens, generally18. In this style of lens the near and distant prescriptions are formedon the lens in a bull's-eye pattern of concentric rings. The nearcorrection, such as center and rigs 20, may be in the middle of the lenswith the distance prescription in the other rings such as 22.Alternatively these locations can be reversed. Placement is dependent onthe lifestyle of the wearer or, in some situations, the pupil size ofthe subject. Large pupils will have the near prescription in the center.For intermediate vision a third zone or ring will be formed between thecenter section and the outer ring. This extra ring will create amultifocal contact lens. A blending of the edges of the zones ispossible.

FIG. 4 is a bifocal contact lens called an aspheric multifocal contactlens, generally 24. In this lens, known in the prior art, both distanceand near 28 prescriptions are placed in the central visual area, on orclose to the pupil. When the aspheric multifocal contact lens wearergazes at an object in the distance the wearer learns to ignore nearobjects. When the wearer focuses on a near object the wearer will learnto ignore far away objects.

The progressive multifocal lens of this invention is preferablymanufactured from a material that contains an ultraviolet absorptioncomponent. Because of the large diameter of the lens this ultravioletabsorption component adds greater protection to the eye by the fact thatthe lens covers the cornea and part of the sclera. This feature aids inlimiting the exposure of the eye to the harmful effects of ultravioletradiation.

FIG. 5 is a process flow chart that shows the progression of a lensselection and manufacturing process used in the production of a lens fora particular patient. This chart starts a to point where a patient walksinto a doctor's office with the intent of getting fitted for contactlenses that will accommodate patients that have unusual needs relatingto fitting contacts. For instance, this lens is helpful in fittingpostoperative eye surgeries, for example. The various acts in theprocess of providing a lens to a patient begins with determining if thesubject or patient has undergone refractive surgery. If the answer tothis question is “yes” that patient would be a good candidate for thefitting of the lenses disclosed herein. If the answer is “no” than thenext question would be whether or not the patient is presbyopic. If theanswer to that question is “yes” than the lens is a good option. If theanswer is “no” the patent may still want or have a need for this lenshowever other lens options are also available. It should be noted thatthese two decisions can be independent or combined. That is a patientcan be fitted with either or both progressive or PRS lenses.

If the answer to either of the above questions is ‘Yes” than the doctoror technician should proceed with fitting of PRS progressive lenses.

The next act is to fit the patient with the standard set of fittinglenses. These lenses will have a range of diameter of approximately 7.34to approximately 8.33 mm in diameter. The doctor will select the lensthat fit best at the periphery.

In the next act the doctor will determine a base curve in relation tocurrent K readings of the treatment area followed by determining thespectacle add and add zone size based on patient's pupil size which canrange from small at 1.5 mm, to medium at 2.0 mm and to large at 2.5 mm.

After the fitting is accomplished by the doctor or technician theappropriate lens is ordered from a manufacturing laboratory with theselected PC, base curve, power add, zone size and material. Thelaboratory will insert these parameters in the focal points. With thesespecifications fixed the laboratory can proceed with manufacturing alens.

The laboratory will select a lens button; buttons of the type used inthese lenses are available from Bausch and Lomb Company, and load thelens button in the lens processing equipment such as a lathe. A jobticket with the desired data for the lens is scanned or read by the lensprocessing equipment and the equipment is ready to form the lens. Abackside or concave side of the lens is formed first. The button isattached to an arbor with the backside of the lens attached to the arborby “blocking” using a water soluble wax compound as a the agent foraffixing the button to the arbor. In this act the lens is centered bythe blocking procedure for processing the front side of the lens.

The arbor is placed in the processing equipment, again this can be alathe in one embodiment, the work ticket is scanned for processing dataand the equipment will process the front side of the lens. On completionof the manufacturing process the arbor and lens are removed fromprocessing and placed in an ultrasonic bath to deblock the completedlens from the arbor. After this process is complete the lens will bechecked for correct power, thickness, and diameter and if it issatisfactory the lens will be shipped to the account that ordered thelens.

The acts above are the usual acts performed in selecting and processinga lens from start to finish however there may be nuances of process flowthat are slightly different from the above depending on unusual factorsrelated to the processing of a lens. The above is not intended to be alimitation on the possible process flow but is intended to show one waythat the process can be performed.

In summary the invention herein is directed to a rigid gas permeableprogressive corneal-scleral contact lens comprising a lens havingsufficient diameter to cover the cornea and a portion of the sclera ofan eye. This lens has an anterior surface with a multifocal segmentincluding an aspheric central zone designed to provide near vision. Italso includes a spherical portion to provide distance vision adjacentthe aspherical central zone. This allows the lens to provide near centeraspheric addition on a true progressive rigid gas permeable contactlens. Continuous vision results throughout the transition from near todistance vision in a controlled rate as the multifocal segment in thecenter of the anterior surface of the lens is a progressive multifocalsegment.

The large diameter of the corneal-scleral, on the order of approximately12.5 mm to approximately 17.0 mm, facilitates the edges of the lensalways being under the upper and the lower eyelids of the wearer's eye.

The large diameter of the lens, when the lens is provided with anultraviolet absorption component also provides the benefit of addingprotection from ultraviolet light to the eye as the lens covers thecornea and part of the sclera.

While the invention is described herein in terms of preferredembodiments and generally associated methods, the inventor contemplatesthat alterations and permutations of the preferred embodiments andmethods will become apparent to those skilled in the art upon a readingof the specification and a study of the drawings.

Another way of summarizing the invention is to say that the invention isa rigid gas permeable progressive corneal-scleral contact lens, havingan anterior surface and a posterior surface, for fitting to an eye. Thisspecial lens is a rigid gas permeable lens of sufficient diameter tocover the cornea and a portion of the sclera of the eye with the radialouter portion of the lens conforming generally to the shape of theocular surface of the eye in the scleral region of the eye. Theposterior surface of the lens covers the corneal region of the eye isselectively spaced from, aligned with, or in eyelid bearing pressurecontact with the corneal region of the eye. In essence this provides adual contact lens that contacts the central portion of the cornea andsimultaneously contacting the sclera. This lens conforms to the corneaand a small portion of the sclera to provide a distributed bearing areafor the lens. The large diameter of the lens provides a solid workableplatform for an aspheric add zone on the convex side of the lensresulting in a true progressive multi-focal rigid gas permeable lens.The anterior surface of the lens has an aspherical segment centrallylocated at a pre-defined diameter that provides correction for an eyethat is experiencing presbyopia, the lens adapted to be opticallyaligned with the lens of the eye and provide optical correction to lightpassing through the eye lens for near vision correction.

The inventors have described the invention above. However, neither theabove description of preferred exemplary embodiments nor the abstractdefines or constrains the invention. Rather, the issued claims variouslydefine the invention. Each variation of the invention is limited only bythe recited limitations of its respective claim, and equivalentsthereof, without limitation by other terms not present in the claim.

What is claimed is:
 1. A rigid gas permeable progressive corneal-scleralcontact lens for use on an eye, the eye comprising a cornea, a limbus,and a sclera, the rigid gas permeable progressive corneal-scleral lenscomprising: a daily use rigid gas permeable continuously progressivecorneal-scleral contact lens having sufficient lens diameter to coverthe cornea and a portion of the sclera of an eye while bridging thelimbus of the eye, the posterior surface of the rigid gas permeablecontinuously progressive corneal-scleral lens being in significantcontact with the central portion of the cornea and a portion of therigid gas permeable continuously progressive corneal-scleral lens incontact with a portion of the sclera providing a distributed bearingarea for the lens; an anterior surface of the rigid gas permeablecontinuously progressive corneal-scleral lens having a continuouslyprogressive multifocal segment being an aspheric central zone providingcontinuously progressive near and intermediate vision correction to theeye; and a spherical portion of the rigid gas permeable continuouslyprogressive corneal-scleral lens to provide distance vision, adjacentthe aspherical central zone of the rigid gas permeable continuouslyprogressive corneal-scleral, and; the rigid gas permeable continuouslyprogressive corneal-scleral lens provides a center aspheric addition toproduce a true continuously progressive rigid gas permeable contact lensthat gives continuous vision correction between near, intermediate, anddistance vision zones of the eye.
 2. The invention in accordance withclaim 1 wherein the anterior surface of the rigid gas permeablecontinuously progressive corneal-scleral lens further providingcontinuous vision results from intermediate to distance visioncorrection to the eye.
 3. The invention in accordance with claim 2comprising a corneal-scleral lens for fitting to a person having anupper and a lower eyelid, the diameter of the lens sufficiently large tohave the edges of the lens always under the upper and the lower eyelidsof the person.
 4. The invention in accordance with claim 1 furthercomprising the lens containing a ultraviolet absorption componentwhereby due to the large diameter of the lens the ultraviolet absorptioncomponent adds protection from ultraviolet light to the eye as the lenscovers the cornea and part of the sclera.
 5. A rigid gas permeableprogressive corneal-scleral contact lens, having an anterior surface anda posterior surface, for fitting to an eye comprising: a rigid gaspermeable lens of sufficient diameter to cover the cornea and a portionof the sclera of the eye; a radial outer portion of the lens conforminggenerally to the shape of the ocular surface of the eye in the scleralregion of the eye; the posterior surface of the lens covering thecorneal region of the eye selectively spaced from, aligned with, or ineyelid bearing pressure contact with the corneal region of the eye. 6.The invention in accordance with claim 5 further comprising: a contactlens contacting the central portion of the cornea and simultaneouslycontacting the sclera.
 7. The invention in accordance with claim 6comprising a lens conforming to the cornea and a small portion of thesclera to provide a distributed bearing area for the lens.
 8. Theinvention in accordance with claim 7 comprising a true continuouslyprogressive multi-focal rigid gas permeable lens.